Rotary piston machine

ABSTRACT

A rotary piston machine operable with a compressible fluid and having a toroidal cylinder containing pistons connected by a unique planetary gearing arrangement to the machine housing and a rotary shaft coaxial with the cylinder, whereby during relative rotation of the housing and shaft, the pistons undergo in a manner such that fluid chambers formed between the pistons alternately expand and contract to draw fluid into and expel fluid from the chambers through intake and exhaust ports in the housing. The planetary gearing includes planet gears located within cavities in the pistons and carried by a planet gear support fixed to the rotary shaft and a reaction sun gear fixed to the machine housing and meshing with the planet gears through openings in the radially inner sides of the cylinder and piston walls. The disclosed embodiment of the machine is a rotary internal combustion engine.

Elite ttes atent 1 Johnson 1 ROTARY PISTON MACHINE [76] Inventor: Richard G. Johnson, 2611 W. Ave.

N-12, Palmdale, Calif. 93550 [22] Filed: July 21, 1972 [21] Appl. No.: 273,815

[52] US. Cl l23/8.47, 418/36 [51] Int. C1. FOZb 53/00 [58] Field of Search 123/847; 418/34, 35, 36

[56] References Cited UNITED STATES PATENTS 1,665,581 4/1928 Deny 418/36 X 1,973,397 9/1934 Stromberg 418/36 X 2,413,590 12/1946 Snyder 418/36 X Primary Examiner-Carlt0n R. Croyle Assistant Examiner-Michael Koczo, Jr. Attorney, Agent, or FirmBoniard 1. Brown TRACT A rotary piston machine operable with a compressible fluid and having a toroidal cylinder containing pistons connected by a unique planetary gearing arrangement to the machine housing and a rotary shaft coaxial with the cylinder, whereby during relative rotation of the housing and shaft, the pistons undergo in a manner such that fluid chambers formed between the pistons alternately expand and contract to draw fluid into and expel fluid from the chambers through intake and exhaust ports in the housing. The planetary gearing includes planet gears located within cavities in the pistons and carried by a planet gear support fixed to the rotary shaft and a reaction sun gear fixed to the machine housing and meshing with the planet gears through openingsin the radially inner sides of the cylinder and piston walls. The disclosed embodiment of the machine is a rotary internal combustion engine.

12 Claims, 10 Drawing Figures EATENTEQ APR 3 0 I974 sum 3 OF 3 ROTARY PISTON MACHINE BACKGROUND OF THE INVENTION Field of the Invention: This invention relates generally to machines of the class which operate with a compressible fluid and more particularly to a novel rotary reciprocating piston machine.

Prior Art: Simply stated, a rotary reciprocating piston machine of the class to which this invention pertains comprises a toroidal cylinder containing pistons which undergo rotational motion around and reciprocating motion along the cylinder in such a way as to affect expansion and contraction of the fluid chambers formed between the pistons. an such a rotary reciprocating piston machine may operate as an internal combustion engine, compressor, or fluid powered motor. The invention will be described in connection with an internal combustion engine.

The existing rotary piston machines employ a wide variety of mechanisms for oscillating the pistons to expand and contract the fluid chambers between, the pistons as the latter undergo movement through their an- ,nular cylinder. One common mechanism for this purpose is a planetary gear arrangement. The present invention is concerned particularly with rotary piston machines which employ such planetary gear type piston oscillating mechanisms.

The existing rotary piston machines of this latter kind suffer from certain disadvantages which the present invention overcomes. These disadvantages result in large part from the fact that the planetary gear mechanisms are situated in their entirety externally of the machine pistons. As a consequence, the machines tend to be quite large in size, relatively heavy, and excessively complex.

SUMMARY OF THE INVENTION The present invention provides an improved rotary piston machine wherein the pistons are connected to the machine housing and shaft by a novel planetary gear arrangement which simplifies the machine, reduces its size and mass, and provides other benefits. This planetary gearing includes a reaction sun gear fixed to the machine housing concentric with the rotary shaft of the machine. Each piston contains an interior cavity which opens radially inward toward the shaft and sun gear through a wall opening in the radially inner side of the piston and a wall opening in the radially inner side of and circumferentially coextensive with the annular cylinder of the machine which contains the pistons.

Fixed to the rotary shaft of the machine is a planetary gear support having arms which project radially outward through the cylinder and piston wall openings into the piston cavities. Rotatably supported on the outer ends of these support arms within the piston cavities are planet gears which project through the openings into meshing engagement with the sun gear. Accordingly, the planet gears rotate on their central rotation axes during relative rotationof the housing and shaft.

Each planet gear is connected to its piston by a crank pin or the like so that rotation of the planet gear imparts endwise or longitudinal reciprocating or oscillating motion to the piston relative to the planet gear. Accordingly, during relative rotation of the machine housing and shaft, the pistons undergo a compound motion involving movement of the pistons longitudinally through or around the cylinder and oscillatory motion of the pistons longitudinally of the cylinder relative to their respective planet gears.

The pitch diameters of the sun and planet gears and the relative angles of the planet gear crank pins are such that during this compound motion of the pistons, the adjacent pistons undergo relative movement toward and away from one another to alternately expand and contract the fluid chambers between the pistons. The housing has fluid intake and exhaust ports for admitting fluid to and exhausting fluid from the chambers as they thus expand and contract. Means are provided for closing or sealing the cylinder wall opening at the radially inner side of each fluid chamber to prevent fluid passage from the chamber through the opening.

The disclosed embodiment of the machine is an internal combustion engine whose fluid chambers provide combustion chambers. In this engine, a combustible fuel mixture is admitted to each combustion chamber as it expands. During the following contraction of the chamber, the mixture is compressed and then ignited by a spark plug or the like. The resulting combustion of the mixture produces forces on the adjacent pistons for driving all the pistons through the cylinder and thereby driving the rotary shaft of the engine in one direction relative tothe engine housing. After combustion, the spent gas is exhausted from each chamber through the engine exhaust port, whereupon the cycle is repeated. Alternatively, the spark plug may be replaced with a fuel injector and the engine may be operated using the diesel or compression ignition cycle.

Both two and four cycle versions of the rotary engine are described. Also described are engines having a single power phase per shaft revolution and engines having two power phases per revolution.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a side elevation of a rotary piston engine according to the invention;

FIG. 2 is an enlarged section through the engine, taken on line 22 in FIG. 3;

FIG. 2A is a fragmentary showing of a fuel injection engine according to the invention;

FIG. 3 is a section taken on line 3--3 in FIG. 2;

FIG. 4 is a fragmentary section through an engine with modified sealing means for the engine combustion chambers;

FIG. 5 is a section taken on line 5-5 in FIG. 4; and

FIGS. 6-9 illustrate various possible engine arrangements within the scope of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to drawing FIGS. 1-3, the illustrated rotary piston machine or engine 10 has a generally flat circular housing 12 containing a concentric annular cylinder 14. Rotatably supported by bearings 16 in the housing, concentric with the cylinder 14 is a shaft 18. This shaft extends beyond opposite sides of the housing and has an enlarged central land 20 between and providing thrust shoulders engagable with the bearings 16 to restrain the shaft against endwise movement relative to the housing. About the outside of the housing are cooling fms 22. The housing has intake and exhaust conduits 24, 26 at one side providing intake and exhaust ports 28, 30 opening to the cylinder 14 at positions spaced therearound.

Within the engine cylinder 14 are pistons 32, in this instance three pistons. Pistons 32 form therebetween fluid chambers 34 which, in the illustrated engine, provide combustion chambers. Each piston is hollow and contains an interior cavity 36. The particular pistons shown have a relatively thin generally uniform wall thickness and are thus relatively light in weight.

Pistons 32 are connected to the engine housing 12 and shaft 18 by a unique planetary gearing arrangement 38 according to the invention. As described presently, this planetary gearing arrangement is such that during relative rotation of the housing and shaft, the pistons undergo a compound motion involving generally rotational motion of the pistons in one longitudinal direction through the cylinder 14 and longitudinal reciprocating or oscillating motion of the pistons relative to one another. This oscillating motion of the pistons occurs in such a way that the combustion chambers 34 undergo alternate expansion and contraction as they effectively move with the pistons longitudinally through the cylinder.

Planetary gearing 38 comprises a reaction sun gear 40 fixed to an inner wall of the housing 12 in concentric surrounding relation to the engine shaft 18. Each piston cavity 36 has openings radially inward toward the shaft and sun gear through a wall opening 42 in the radially inner side of the piston and a wall opening 44 in the radially inner side of and circumferentially coextensive with the cylinder 14. This cylinder wall opening forms annular concentric shoulders 46 at opposite sides of the opening, concentric with the cylinder and shaft.

Fixed to the engine shaft 18 within the housing 12 is a spider-like planet gear support 48. This gear support has arms 50 which extend radially outward through the cylinder and piston wall openings 44, 42 into the piston cavities 36. Fixed in the outer end of each support arm 50, within the respective piston cavity 36, is a bearing 52 with its axis parallel to the engine shaft. A shaft 54 is rotatable in each bearing 52. Rigid in one end of each shaft 54 is a planet gear 56 which projects radially inward through the respective piston wall opening 42 and the cylinder wall opening 44 into meshing engagement with the sun gear 40. From this description, it is apparent that during relative rotation of the housing 12 and shaft 18, the planet gears 56 undergo rotation on their central rotation axes.

Each planet gear 56 is connected by means 58 to its respective piston 32 in such a way that rotation of the gear on its central axis imparts a longitudinal reciprocating or oscillating motion to the piston relative to the planet gear. The particular connecting means shown comprise crank pins 60 fixed to the planet gears 56 and to crank arms 62 on the planet gear shafts 54. The two crank pins 60 for each planet gear are aligned on a common axis parallel to and laterally displaced from the planet gear axis. Crank pins 60 rotatably mount slides 64 which slide in slots or grooves 66 formed in the inner walls of the pistons 32. These slots of each piston are disposed in a common plane normal to the longitudinal axis of the piston and cylinder 14. From this description, it is evident that rotation of each planet gear drives its piston in a back and forth oscillating motion relative to the gear.

Means 68 are provided for closing or sealing the cylinder wall opening 44 at the radially inner side of each combustion chamber 34. Sealing means 68 comprise curved flanges 70 on the pistons. Each piston has a sealing flange 70 which extends from one end of the piston, across the radially inner side of the adjacent combustion chamber 34, into fluid sealing relation with the radially inner side of the adjacent piston. These flanges, as well as the radially inner longitudinal edges 72 of the pistons slide on and are disposed in fluid sealing relation with the annular housing shoulders 46. The pistons are thus supported against radial inward movement by the shoulders 46. Hence, the fluid pressure in the combustion chambers cannot urge the pistons radially inward and adversely affect their fluid sealing relation with the cylinder.

FIGS. 4 and 5 illustrate an alternative sealing arrangement for the combustion chambers. In this case curved sealing plates 74 are fixed to a central disk of the planet gear support 48a opposite each combustion chamber 34. These sealing plates may slide on and be disposed in fluid sealing relation to the housing shoulders 46 or to the insides of the housing 12, or both, and extend endwise into fluid sealing relation with the inner sides of the adjacent pistons 32. Alternatively, sealing plates 74 may be spaced from the shoulders 46, or the shoulders may be eliminated, and the plates may be sealed along their edges to the housing side walls. This eliminates the necessity of maintaining the concentricity of the engine shaft and the shoulder surfaces 46. Both the sealing flanges 70 and sealing plates 74 are longitudinally dimensioned to remain in sealing relation with the adjacent pistonsthroughout the range of their longitudinal oscillating motion.

From the description to this point, it is apparent that during relative rotation of the engine housing 12 and shaft 18, the pistons 32 undergo the compound motion discussed earlier. This compound motion involves generally rotational motion of the pistons in one direction through the cylinder 14 and simultaneous oscillatory motion of the pistons longitudinally of the cylinder. This compound motion occurs in such a way that adjacent pistons move toward and away from one another to alternately expand and contract the combustion chambers 34 as they move with the pistons through the cylinder. The particular engine shown is a three piston four cycle engine wherein each combustion chamber undergoes expansion during its movement through two diametrically opposed portions of the cylinder (i.e., from A to B and from C to D in FIG. 2) and contraction during its-movement through the remaining-two diametrically opposed 90 portions of the cylinder (i.e., from B to C and from D to A). Each chamber is contracted to its minimum volume in positions A and C and expanded to its maximum volume in positions B and D. The engine exhaust port 30 is located and sized to communicate with each combustion chamber during its contraction from B to C. The engine intake port 28 is located and sized to communicate with each combustion chamber during its expansion from C to D. Each combustion chamber, when at position A, registers with a spark plug 76.

The above operating sequence of the engine is achieved by providing the sun gear 40 and planet gears 56 with a 2zlgear ratio and angularly displacing the planet gear crank 60 by l20 angles, as shown.

The engine operation will now be explained, assuming that the pistons 32 are moving clockwise in FIG. 2 through the cylinder 14, either by virtue of cranking of the engine with a starter or actual engine operation. As each combustion chamber 34 undergoes expansion from C to D, it draws in a charge of fuel mixture from the engine intake port 28. During following contraction of the chamber from D to A, the fuel mixture is compressed.

The engine ignition system (not shown) is timed to fire the spark plug '76 upon arrival at position A of each combustion chamber 34 with its compressed fuel charge. The fuel charge is thereby ignited to produce gas pressure driving forces on the adjacent pistons 32 leading and following the chamber relative to the direction of movement of the pistons through the cylinder 14. The driving force on the leading piston drives the latter forwardly in the cylinder, relative to its planet gear 56, thereby rotating the planet gear clockwise and producing a clockwise driving torque in the shaft 18 through the planet gear support 48. In this regard it will be observed that the moment of ignition, the crank pin 60 of the leading piston planet gear is beyond dead center position relative to the longitudinal piston axis. Accordingly, the gas pressure driving force on the piston rotates the planet gear clockwise, as described.

On the other hand, the planet gear crank pin 60 of the following piston 32 is just approaching dead center position relative to the longitudinal piston axis so that the crank pin, which is rotating clockwise with its planet gear 56, is driving the piston forwardly relative to the gear. The gas pressure driving force on the piston opposes this forward crank pin driving force on the piston. However the clockwise driving torque exerted on the shaft 18 and planet gear support 48 by the leading piston and the momentum of the rotating parts carries the traveling piston crank pin beyond dead center position. The gas pressure driving force on the following piston then becomes effective to drive the piston rearwardly relative to its planet gear 56 and rotate the latter clockwise for aiding the driving torque produced by the gas pressure driving force on the leading. piston.

The above action occurs three times during each revolution of the engine shaft 18 to drive the latter in continuous clockwise rotation. The engine thus has three power phases per shaft revolution.

Following combustion, each combustion chamber 34 undergoes contraction from B to C in FIG. 2. The spent combustion gas in the chamber is thus expelled through the engine exhaust port 30. The chamber then undergoes expansion from C to D to draw in a fresh fuel charge through the engine intake port 28, after .which the chamber proceeds through its next operating cycle.

The engine just described is obviously a four cycle engine in which each combustion chamber undergoes intake, compression, expansion, and exhaust phases during each complete revolution.

It will be immediately evident to those versed in the art that a rotary piston engine according to the invention may be designed to have various numbers of pistons, either two or four cycle operation, and two or more power phases per shaft revolution. FIGS. 6-9 i1- lustrate some of the possible engine arrangements. FIG. 6 shows a four piston, four cycle engine with a 2:1 gear ratio between the planet and sun gears. FIG. 7 shows a six piston four cycle engine with two spark plugs and two sets of intake and exhaust ports. This engine has a 4:1 planetary gear ratio. FIG. 8 shows a three piston, two cycle engine having a 1:1 planetary gear ratio. FIG. 9 shows a two piston, two cycle engine with a 1:1 gear ratio. The engines of FIGS. 6-9 are essentially the same as the engines of FIGS. 1-5 and differ from the latter engines only in the number of pistons and planetary gear ratio. The operation of the four cycle engines of FIGS. 6 and 7 is essentially the same as that of FIGS. 1-5 except that in the six piston engine of FIG. 7, each combustion chamber undergoes intake compression, expansion, and exhaust phases during each half revolution of the engine shaft. In the two cycle engines of FIGS. 8 and 9, each combustion chamber undergoes a single contraction during one half of each engine shaft revolution during which intake and compression occur and a single expansion during the other half of each revolution during which combustion and exhaust occur. As in any two cycle engine the intake and exhaust phases depend upon scavenging means which may be provided by an auxiliary blower (not shown).

While the illustrated engines utilize spark ignition, it will be readily apparent to those versed in the art that the engines may be operated with a diesel or compression ignition cycle by replacing the spark plug with a fuel injector 76a, as shown in FIG. 2A. In such a fuel injection engine, of course, only air charges enter the cylinder through its intake.

The present rotary piston engines have numerous features and advantages. Among these are the follow- 1. No valves or valve gear are needed since ports are used.

2. The planetary gear assembly with its shaft, crank arm and crank pins can be dynamically balanced.

3. The crank arm of the planetary gear crank pins can be chosen within limits. This determines the displacement of the engine and also the forces produced. The crank arm is about one half the pitch radius of the planetary gears and is determined by the pin diameter needed for strength and also the size of the slider piece.

4. The pistons are hollow and the planetary gears are placed inside the pistons except for the gear portions which are required to protrude from the pistons in order to mesh with the fixed sun gear. In this way the slots in the sides of the pistons are inside and the outer piston surfaces are smooth in order to make sealing easier. Also, the hollow thin walled piston design provides for minimum weight.

5. Only one spark plug (or fuel injector) is needed for the entire engine instead of one per combustion chamber (cylinder) in a conventional engine.

6. The only parts that do not rotate at constant angular velocity are the pistons themselves.

7. If necessary for strength, each piston may have two planet gears, one on each side, each meshing with a separate sun gear.

8. The intake and exhaust ports can be located on one or both sides or on the outer circumferential surface of the engine housing. The port shape can be varied to produce very rapid opening and closing or other desired valving characteristics.

9. Either spark ignition or fuel injection can be used. If spark ignition is used, as shown, the spark plug is cut off from the combustion chamber soon after ignition, thereby allowing cooling of the spark plug.

I 10. The compression ratio can be adjusted by changing the arc length of the pistons or the locations of the ports.

I l. The pistons travel in a circular path with oscillatory motion superimposed upon the overall rotary motion. There is no change in direction of piston motion only changing magnitude, thereby reducing inertia forces compared to those of reciprocating pistons.

12. The centrifugal forces generated by the mass of the pistons is carried by the outer circumferential surface of the engine cylinder, while the centrifugal forces generated by the planetary gear support and planet gears and the crankshaft are carried by the crank shaft itself. In contrast to reciprocating piston engines, the crank shaft and connecting links do not have to carry the mass of the pistons.

13. More than one engine can be combined on a common shaft.

14. The spark plug or fuel injector can be located on the side or outer circumferential surface of the engine housing to promote the most efficient combustion.

15. The intake and exhaust port areas are large in order to provide high volumetric efficiency of the engine.

16. The exhaust port emits exhaust gas almost continuously whereby high temperature is maintained and the operation of a thermal or catalytic reactor will be more efficient in reducing exhaust emissions.

1?. Due to lighter inertia loads, the engine can be operated at high rotational speeds. This will result in lower exhaust emissions due to lessened effect of wall quenching, crevice quenching and blowby of unburned fuel.

18. Each piston is equivalent in function to two reciprocating pistons and each planetary connecting link is equivalent to two conventional connecting rods.

19. The engine has no theoretical line contact. All sealing contact is surface contact so good sealing is provided, thus permitting utilization of high compression ratios, whereby the diesel cycle can be utilized.

20. The hollow piston design coupled with the crank case space allows air and oil mist to circulate inside the engine to provide lubrication and cooling in addition to a pressure lubrication system. Also the above design allows the utilization of a positive crankcase ventillation system in which any gas escaping from the combustion chambers and entering the crankcase is returned to the in take for reburning.

The inventor claims:

1. A rotary piston machine operable with a compressible fluid comprising:

a housing containing a toroidal cylinder,

a shaft rotatably supported in said housing concentric with said cylinder,

a reaction sun gear fixed to said housing concentric withsaid shaft,

pistons movable longitudinally through said cylinder and defining fluid chambers between the adjacent piston ends,

each piston containing an internal cavity which opens radially inward toward said shaft and sun gear through a wall opening in the radially inner side of the piston and a wall opening in the radially inner side of and circumferentially coextensive with said cylinder,

sealing means closing said cylinder wall opening be-.

tween adjacent pistons,

a planet gear support fixed on said shaft having arms projecting radially outward through said cylinder and piston wall openings into said piston cavities,

planet gears rotatably mounted on said support arms within said piston cavities and projecting radially inward through said piston and cylinder wall openings into meshing engagement with said sun gear, whereby said planet gears rotate on their central axes during relative rotation of said housing and shaft,

means connecting said planet gears and their respective pistons for imparting a longitudinal reciprocating motion to said pistons relative'to their planet gears during rotation of the latter gears on their central rotation axes in such manner that during relative rotation of said housing and shaft in one direction, said pistons undergo relative longitudinal movement in one direction through said cylinder and longitudinal reciprocating motion relative to one another to alternately expand and contract said fluid chambers, and

said housing having port means opening to said cylinder.

2. A rotary piston machine according to claim 1 wherein:

said connecting means comprise crank means.

3. A rotary piston machine according to claim 2 wherein:

saidcrank means comprise crank pins on said planet gears spacedfrom and parallel to the rotation axes of the planet gears and engaging in slots in the walls of the piston cavities transverse to the longitudinal axes of the pistons.

4. A rotary piston machine according to claim 1 wherein: said sealing means comprises a curved sealing flange and extending from one end of each piston, across the radially inner side of the adjacent fluid cham her, into fluid sealing relation with the radially inner side of the adjacent piston and having its longitudinal edges disposed in fluid sealing relation to said housing.

5. A rotary piston machine according to claim 1 wherein:

said sealing means comprise curved sealing flanges fixed to said planet gear support and extending across the radially inner sides of said fluid chambers, respectively, into fluid sealing relation with the radially inner sides of the adjacent pistons and having their longitudinal edges disposed in fluid sealing relation to said housing.

6. A rotary piston machine'according to claim 1 including:

means on said housing supporting said pistons against radial inward movement toward said shaft.

7. A rotary piston machine according to claim 1 including:

means on said planetary gear support supporting said pistons against radial inward movement toward said shaft.

8. A rotary piston machine according to claim 1 wherein:

said machine is an internal combustion engine, and

said fluid chambers comprise combustion chambers for receiving a fuel-air mixture and said cylinder 9 defines at least one fuel ignition zone through which each chamber moves at the conclusion of a contraction phase of the respective chamber, such that combustion of said mixture occurs during the immediately following chamber expansion phase.

9. A rotary piston machine according to claim 8 wherein:

said machine is a two cycle spark ignition engine including a spark plug for igniting said mixture within each chamber as it moves through said'combustion zone, and said port means are located to open to each chamber at the start of said contraction phase and the end of said expansion phase of the respective chamber.

10. A rotary piston machine according to claim 8 wherein:

said machine is a two cycle fuel injection engine including a fuel injector for injecting fuel into each chamber as it moves through said combustion zone, and said port means are located to open to each chamber at the start of said contraction phase and the end of said expansion phase of the respective chamber; I

11. A rotary piston machine accordingto claim 8 wherein:

wherein:

said machine is a four cycle fuel injection engine including a fuel injector for injecting fuel into each chamber as it moves through said combustion zone, and said port means are located to open to each chamber during the expansion phase immediately preceding said contraction phase-of the respective chamber and during the contraction phase immediately following said combustion expansion phase of the respective chamber.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,807,368 Dated April 30, 1974 Inventods) Richard G. Johnson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the Abstract, line 6, after "undergo" insert -simul taneous rotational motion around and reciprocating motion along the cylinder; 6

Engncd and Scaled this twenty-fourth Day Of February 1976 [SEAL] Arrest:

RUTH. C. M A-SON C. MARSHALL DANN Arresting Officer (mnmissiuner ujlatenrs and Trademarks O 

1. A rotary piston machine operable with a compressible fluid comprising: a housing containing a toroidal cylinder, a shaft rotatably supported in said housing concentric with said cylinder, a reaction sun gear fixed to said housing concentric with said shaft, pistons movable longitudinally through said cylinder and defining fluid chambers between the adjacent piston ends, each piston containing an internal cavity which opens radially inward toward said shaft and sun gear through a wall opening in the radially inner side of the piston and a wall opening in the radially inner side of and circumferentially coextensive with said cylinder, sealing means closing said cylinder wall opening between adjacent pistons, a planet gear support fixed on said shaft having arms projecting radially outward through said cylinder and piston wall openings into said piston cavities, planet gears rotatably mounted on said support arms within said piston cavities and projecting radially inward through said piston and cylinder wall openings into meshing engagement with said sun gear, whereby said planet gears rotate on their central axes during relative rotation of said housing and shaft, means connecting said planet gears and their respective pistons for imparting a longitudinal reciprocating motion to said pistons relative to their planet gears during rotation of the latter gears on their central rotation axes in such manner that during relative rotation of said housing and shaft in one direction, said pistons undergo relative longitudinal movement in one direction through said cylinder and longitudinal reciprocating motion relative to one another to alternately expand and contract said fluid chambers, and said housing having port means opening to said cylinder.
 2. A rotary piston machine according to claim 1 wherein: said connecting means comprise crank means.
 3. A rotary piston machine according to claim 2 wherein: said crank means comprise crank pins on said planet gears spaced from and parallel to the rotation axes of the planet gears and engaging in slots in the walls of the piston cavities transverse to the longitudinal axes of the pistons.
 4. A rotary piston machine according to claim 1 wherein: said sealing means comprises a curved sealing flange and extending from one end of each piston, across the radially inner side of the adjacent fluid chamber, into fluid sealing relation with the radially inner side of the adjacent piston and having its longitudinal edges disposed in fluid sealing relation to said housing.
 5. A rotary piston machine according to claim 1 wherein: said sealing means comprise curved sealing flanges fixed to said planet gear support and extending across the radially inner sides of said fluid chambers, respectively, into fluid sealing relation with the radially inner sides of the adjacent pistons and having their longitudinal edges disposed in fluid sealing relation to said housing.
 6. A rotary piston machine according to claim 1 including: means on said housing supporting said pistons against radial inward movement toward said shaft.
 7. A rotary piston machine according to claim 1 including: means on said planetary gear support supporting said pistons against radial inward movement toward said shaft.
 8. A rotary piston machine according to claim 1 wherein: said machine is an internal combustion engine, and said fluid chambers comprise combustion chambers for receiving a fuel-air mixture and said cylinder defines at least one fuel ignition zone through which each chamber moves at the conclusion of a contraction phase of the respective chamber, such that combustion of said mixture occurs during the immediately following chamber expAnsion phase.
 9. A rotary piston machine according to claim 8 wherein: said machine is a two cycle spark ignition engine including a spark plug for igniting said mixture within each chamber as it moves through said combustion zone, and said port means are located to open to each chamber at the start of said contraction phase and the end of said expansion phase of the respective chamber.
 10. A rotary piston machine according to claim 8 wherein: said machine is a two cycle fuel injection engine including a fuel injector for injecting fuel into each chamber as it moves through said combustion zone, and said port means are located to open to each chamber at the start of said contraction phase and the end of said expansion phase of the respective chamber.
 11. A rotary piston machine according to claim 8 wherein: said machine is a four cycle spark ignition engine including a spark plug for igniting said mixture within each chamber as it moves through said combustion zone, and said port means are located to open to each chamber during the expansion phase immediately preceding said contraction phase of the respective chamber and during the contraction phase immediately following said combustion expansion phase of the respective chamber.
 12. A rotary piston machine according to claim 8 wherein: said machine is a four cycle fuel injection engine including a fuel injector for injecting fuel into each chamber as it moves through said combustion zone, and said port means are located to open to each chamber during the expansion phase immediately preceding said contraction phase of the respective chamber and during the contraction phase immediately following said combustion expansion phase of the respective chamber. 